Fukiic and piscidic acid esters from the rhizome of Cimicifuga racemosa and the in vitro estrogenic activity of fukinolic acid.

Hydroxycinnamic acid esters of fukiic acid and piscidic acid were isolated from a 50% ethanolic extract obtained from the rhizomes of Cimicifuga racemosa (Ranunculaceae). Besides 2-E-caffeoylfukiic acid (fukinolic acid), 2-E-feruloylfukiic acid (cimicifugic acid A), 2-E-isoferuloylfukiic acid (cimicifugic acid B), 2-E-feruloylpiscidic acid (cimicifugic acid E) and 2-E-isoferuloylpiscidic acid (cimicifugic acid F), free caffeic, ferulic and isoferulic acids were isolated. The estrogenic activity of fukinolic acid was shown by increased proliferation (126% at 5 x 10(-8) M) of an estrogen dependent MCF-7 cell system with reference to estradiol (120% at 10(-10) M).